Libertarianism is flawed in many ways, yes, and its proponents do not consider its peripheral realities. To what you wrote I would add the observations that markets are created from the will of a central authority, and that the mob can become tyranny when not restrained by a more level-headed authority in whatever form.
These critiques (and more) are prominent in the neoreactionary literature on liberalism/libertarianism (but nowadays they have more important things to talk about). An interesting hypothesis of neoreaction is that liberal ideals, or even a libertarian world, will invariably lead to democratic socialism -- due to the power of the mob.
Personally, the foundation of my disillusionment with liberalism/libertarianism is the fact that people are so much more than economic units, and that collectivism trumps individualism. What's important is preservation of heritage, culture, tradition, creation of art in all its beautiful forms, and the maximization of humanity's potential.
I can't see liberalism/libertarianism getting us much further than working on advertising systems to push junk food, while NASA spends half its time making reports to get a few more handouts, and cultures worldwide are systemically destroyed in the name of economic growth.